Scissors for medical use were, up to a short time ago, made of stainless steel intended to be sterilized for repeated use. However, even with sterilization, the problem of infection exists. In order to overcome this problem, disposable scissors were produced. These are generally constituted by short stainless steel blades attached to the pivot of plastic handles.
An example of such scissors is described and claimed in German Patent publication No. 3,212,124 which discloses surgical scissors with disposable blades which can be attached and detached from the handles. The handles are not disposable and require sterilization for reuse.
Many of these prior art scissors suffer from the disadvantage that the pivot thereof retains the blades in intimate contact, thereby trapping bacteria and preventing penetration of sterilization steam or fluid.
An effort to overcome this problem is described and claimed in U.S. Pat. No. 3,688,402 to Shannon. Each blade of the scissors of Shannon comprises a flat mounting part at the pivot, an outer blade or cutting part which is at a slight angle to said flat part, and an inner camming part at an angle to the flat part which is slightly greater than the angle of the blade part and has a stop means at its outer end. The shape of the blades assures that when the handles are closed, the blades come into pointwise contact with each other along their cutting edges during the shearing action. Yet, when the scissors are closed, a space is defined between the blades at the pivot to permit effective sterilization.
There are also known in U.S. Pat. No. Des. 285,167 and Israel Design Registrations Nos. 9605, 9606, and 9607 to the present applicants, disposable scissors of this kind wherein the handle is provided with a triangular extension extending from the pivot in the direction of the blade.
These prior art scissors having pointwise shearing action suffer from the disadvantage that the blades are loosely supported on the handles around the pivot point with which the handles are connected to each other. This often causes impaired shearing action. Furthermore, the blades are relatively thin and can bend under the stress of cutting a hard object.